Press control



Sept.5, 1939. WGMAU 7 2,171,586

' PRESS CONTROL Filed Dec. 6, 1937 z/ M FIG-3 INVENTOR WILLIAM G. MAU

ATTORNEYS Patented Sept. 5, 1939 UNITED STATES PATENT OFFECE PRESS CONTROL Application December 6, 1937, Serial No. 178,209

7 Claims.

This invention relates to improvements in a control for pressing machines, and more particularly to such a control applicable to laundry and garment pressing machines.

One of the objects of the present invention is the provision of a control valve for the fluid supply for a fluid motor actuated pressing machine wherein a balanced piston valve is movable into either of two positions for supply or exhaust of pressure fluid to the motor and wherein the valve at one period of its operation will be returned to exhaust position and at another period of its operation will be maintained in supply position upon movement thereto. My improved control valve may also be incorporated in control mechanism including means preventing movement of the valve to its final maintained position until the press is safely closed. My invention may also be incorporated in a safety two-hand control for preventing injury to the hands of an operator while the press is closing.

Other novel features and advantages of my invention will be apparent from the accompanying drawing and description and the essential features will be summarized in the claims.

In the drawing, Fig, l is an end elevation of a pressing machine in open position with my improved control mechanism shown diagrammatically; Fig. 2 is a similar view showing in full line position the pressing parts in safe-closed position and in dotted lines the final pressing position of the members, the control mechanism being shown diagrammatically in position corresponding to the'press parts shown in full lines; while Fig. 3 is a diagrammatic view of the control mechanism of Figs. 1 and 2, the position corresponding to the fully closed position of the pressing members.

I have illustrated my improved control mechanism as applied to a laundry or garment press having a frame It supporting a pressing bed II and also supporting a lever 2 which carries a pressing head |3 into and out of engagement with the bed upon oscillation of the lever by toggle l4 under the influence of the cylinder and piston motor l5. A spring l6 serves normally to return the pressing head to open position.

The fluid supply for motor comprises a conduit l! and a casing l8. The casing houses for reciprocation therein a balanced piston valve l9 which in fluid cut-off and exhaust position as shown in Fig. 1 establishes communication between conduit I! and exhaust port 20. The valve IS in Fig. 3 is shown in supply position where it establishes communication between conduit l1 and a fluid supply port 2|. It will be noted with reference to Figs. 1 and 2 that the pressure fluid entering at port 2| is available to return the valve I}! to its fluid cut-off position because of the pressure of the fluid in the left-hand end of casing l8. Means is provided for evacuating this end of the casing at the proper time to relieve the pressure therein and prevent further biasing of the valve in either direction. To this end the casing I8 is provided with a central cylindrical extension |8a in which is reciprocably housed a piston 22 supported by a rod 22m from valve l9 and movable therewith. In the extension |8a is an additional exhaust port 23. This port is normally ineffective to evacuate the left end of I casing l8 with the parts in the position of Figs. 1 and 2, but when the parts move to the position of Fig. 3 with valve IS in supply position, port 23 is opened and the pressure trapped in the left end of casing I8 is evacuated.

Means is provided for preventing the movement of valve l9 to the self-maintained position of Fig. 3 until the press is safely closed to a point Where the operator will not have a hand caught between the approaching pressing members. For this purpose I provide a stop 24 adapted to engage the manual 25 which as shown is operatively connected with valve H3. The stop 24 is rigidly mounted on a shaft 26 which shaft is provided with a crank 21 and the crank in turn is pivotally connected with a rod 28 which passes through a bracket Ma on toggle l4. The rod 28 is provided with collars 28a. and 28b and is biased in a direction to normally maintain the stop in the position of Figs. 1 and 2 by a spring 29. It will be understood that the manual and the stop means are suitably mounted on the frame II] at the front of the machine.

Preferably the parts thus far described are part of a safety two-hand control. To this end a conduit 33 in communication with the combined supply and exhaust conduit I7 is provided with a normally closed inlet valve 3|a housed in casing 3| and supplied with pressure fluid through conduit 32. The valve 3|a is biased toward closed position by spring 33 and is operable by means of manual Preferably manuals 34 and 25 are so spaced apart on the frame as to require a hand of the operator on each of them for their coincidental operation.

The operation of my improved control mechanism is as follows: With the parts in the position of Fig. 1, the operator arranges the lay of the Work on bed I! and actuates manuals 34 and 25. With the stop 24 in position, the valve i9 cannot be moved beyond the position of Fig, 2 which is sufficient to close the exhaust port 20 but not sufiicient to open the inlet port 2|. If valve 3|a is opened, fluid is supplied through conduit 32 and conduits and ll to motor I5, causing the pressing head 53 to close. If manual 34 is released, pressure fluid ceases to be supplied to motor l5 and the pressing head will stop. If manual 25 is released, pressure fluid is exhausted at port 20 and the press will not close.

If both manuals are held depressed until the parts reach the full line position of Fig. 2, further straightening of toggle l4 causes the bracket Mo to engage collar 2% to exert a pull on rod 28 which serves to move the stop 24 to the ineffective position of Fig. 3. Up until this time there has been pressure fluid in the left-hand end of casing l8 acting against the left-hand face of piston valve l9 tending always to return this valve to the right-hand end of casing 18 .which is the fluid cut-off and exhaust position. Upon removal of stop 24, manual 25 may be actuated through a second stage of movement as shown in Fig. 3 until it engages a limiting stop. This causes valve I9 to establish communication between port 2! and conduit II. If the pressure fluid is maintained trapped in the left-hand end of casing !8, then upon the release of manual 25 the valve l9 would return toward the right. To prevent this, when the parts move to the position of Fig. 3, piston 22 uncovers port 23 evacuating the left end of casing [8. Both manuals may now be released, permitting the valve 3la to close but the press will remain closed because piston valve I9 is now in balanced condition and will remain in the position of Fig. 3 until manually returned to exhaust position by the operator. When this occurs the press will open under the action of spring l6 and stop 24 will return to the position of Fig. 1 for the next operation.

My improved mechanism is adapted to produce another type of operation sometimes desirable in pressing machines, namely, the building up of varying pressures between the coacting pressing members. Referring to Fig. 2 it will be noted that valve I 9 is in an intermediate position where exhaust through port 20 is prevented and supply through port 2| is not yet established. With the parts in this position the operator may depress manual 34 until just sufficient air has entered through valve 3|a. to build up a very light pressure between the pressing members H and it. This pressure may then be increased by different amounts by simply opening the valve am for short periods to add varying amounts of pressure fluid to motor l5. During this operation of course valve I9 would be maintained in the position of Fig. 2. If then it were desired to leave the press closed, manual 25 could be moved to the position of Fig. 3 with the efiect previously described.

What I claim is:

1. In a pressing machine having relatively movable pressing members and power means for causing relative movement between them. control means for said power means having two stages of operation, a first stage from power cut-off position to intermediate position effective to supply power to said power means to eflect relative closing movement of said pressing members, and a second stage from intermediate to full operated position for maintaining power supply to said power means, pressure fluid actuated means normally effective to return said control means from intermediate to power cut-off position, means responsive to relative closing movement of said pressing members for controlling said second stage of operation, and means for releasing pressure fluid from said fluid actuated means to render it ineffective after second stage operation of said control means.

2. In a pressing machine having relatively movable pressing members and fluid actuated power means for causing relative movement between them, a pressure fluid supply for said power means including a valve casing and a balanced piston valve reciprocable therein, a combined supply and exhaust conduit for sa d power means communicating with said casing, an exhaust port in said casing, a pressure fluid supply port near one end of said casing, said parts being so arranged that said valve has a cut-off position in which it establishes communication between said conduit and said exhaust port and has a supply position in which it establishes communication between said conduit and said supply port, and means for evacuating the said one end of said casing by movement of said valve to supply position.

3. The combination of claim 2 including a normally closed fluid supply valve communicating with said combined supply and exhaust conduit, a manual for each valve, and said manuals being spaced to require a hand of the operator on each of them for their coincidental operation.

4.. The combination of claim 2 including a normally closed fluid supply valve communicating with said combined supply and exhaust conduit, a manual for each valve, said manuals being spaced to require a hand of the operator on each of them for their coincidental operation, and means preventing movement of said piston valve to supply position until said pressing machine is safely closed.

5. The combination of claim 2 in which the last named means comprises an additional exhaust port in the said one end of said casing, and means normally closing said additional port and movable to open said port by movement of said piston valve to supply position.

6. In a pressing machine having relatively movable pressing members and fluid actuated power means for causing relative movement between them, a pressure fluid supply for said power means including a valve casing and a balanced piston valve reciprocable therein, a combined supply and exhaust conduit for said power means communicating with said casing intermediate its ends, an exhaust port near one end of said casing, a pressure fluid supply port near the other end of said casing, said parts being so arranged that said valve has an exhaust position in which it establishes communication between said conduit and said exhaust port and said valve I has a supply position in which it establishes communication between said conduit and said supply port and said valve has an intermediate position cutting off both ports, another fluid supply conduit communicating with said combined supply and exhaust conduit, and a normally closed inlet valve in said last named conduit.

7. In a pressing machine having relatively movable pressing members and fluid actuated. power means for causing relative movement between them, a pressure fluid supply for said power means including a valve adapted to remain in either fluid supply or fluid cut-off position when placed there, said valve including pressure fluid actuated means normally eifective to move said valve to fluid cut-off position, means for rendering said last named pressure fluid actuated means ineffective when said valve is moved to fluid supply position, other means for supplying fluid to said power means for preliminarily closing said press, and means for preventing movement of said valve to fluid supply position until said pressing members reach a safe-closed position.

WILLIAM G. MAU. 

